[fiatmillie1969]

  hi everyone, just bought 5 saddlebacks to rear 4 meat. Unfortunately the guy didn't worm or treat 4 parasites externally mmm. So they defo have lice. Used olive oil n nit comb which is working well. Any advice welcome. X

[Marches Farmer]

Vet can supply a pour on treatment.

[HappyHippy]

If they've never been treated with anything, I'd be more inclined to jab them with ivermectin/noromectin now to ensure they're not trying to cope with a worm burden while growing.
Your vet should be able to do it easily and give you tips on injecting while they're at it  Better to treat now IMHO.
HTH